288 RESEARCHES ON FUNGI 



and therefore resembled that shown in Fig. 122 (p. 287), whilst others 

 were cut parallel to the gill- edges and in such a way that one side 

 of each section was made up of the free autodigesting edges of several 

 gills. In all cases, the sections, immediately after being cut, were 

 placed in a compressor cell in order to prevent undue transpiration. 

 Where a section included free gill-edges, it was turned upside down 

 so that the edges looked upwards. On observing the sections with 

 the low power of the microscope, it was possible not only to see the 

 cystidia stretching across the interlamellar spaces but also to watch 

 their disappearance. 



With sections such as those just described one can make the 

 following observations. At about 0-5 mm. above the extreme edge 

 of each gill the cystidia, as indicated by a slight diminution in 

 diameter, are already beginning to disappear. Nearer to the 

 autodigesting gill-edge, they have become very much reduced in 

 diameter (Fig. 122, p. 287, k k, in zone h). Still nearer to the gill- 

 edge, they have become detached from one gill and partly withdrawn 

 to the other gill, usually to the one from which they originated 

 (/ I, in zone h), or, as sometimes happens, they have become broken 

 in two either in the middle or near one end {m in zone h). The cystidia 

 which are just above the zone of spore- discharge have become 

 reduced to practically nothing, so that it is difficult or impossible 

 to detect any trace of them. 



The disappearance of individual cystidia was observed in a con- 

 siderable number of instances. Stages in the autodigestion of six 

 cystidia are shown in Fig. 123. The time which elapsed between 

 the initial shrinking of a cystidium and its total disappearance was 

 found to be less than half an hour. It took ten minutes for the 

 cystidium represented at C to pass from the fully turgid condition 

 shown at a to the final stage shown at^, and the break in the cystidium 

 represented at D occurred fourteen minutes after the initial thinning 

 was detected. 



One may ask : what becomes of the fluid which is liberated 

 from a cystidium during its autodigestion ? Doubtless, part of it 

 simply evaporates ; but it is probable that some of it is drawn by 

 capillarity into the interhyphal spaces of the subhymenium and 

 trama. If there were no absorption of this kind, it seems likely 



